code: def test_roi_images(rng):
      img1 = rng.random((5, 5, 5))
      img2 = np.zeros((5, 5, 5))
      img2[2, 2, 2] = 1
      img3 = np.zeros((5, 5, 5))
      img3[0, :, :] = 1
      images = [(img1, np.eye(4)), (img2, np.eye(4)), (img3, np.eye(4))]
      show_m = horizon(images=images, return_showm=True)
      analysis = window.analyze_scene(show_m.scene)
      npt.assert_equal(analysis.actors, 0)
      arr = window.snapshot(show_m.scene)
      report = window.analyze_snapshot(
          arr, colors=[(0, 0, 0), (255, 255, 255)]
      )
      npt.assert_array_equal(report.colors_found, [True, True])
      show_m = horizon(
          images=images, roi_images=True, return_showm=True
      )
      analysis = window.analyze_scene(show_m.scene)
      npt.assert_equal(analysis.actors, 2)
  
file_path: dipy/dipy/viz/tests/test_apps.py
imports: import os
  import warnings
  import numpy
  import numpy.testing
  import pytest
  from dipy.data import DATA_DIR
  from dipy.io.stateful_tractogram import Space, StatefulTractogram
  from dipy.io.utils import create_nifti_header
  from dipy.testing import check_for_warnings
  from dipy.testing.decorators import use_xvfb
  from dipy.tracking.streamline import Streamlines
  from dipy.utils.optpkg import optional_package
  from dipy.testing.decorators import set_random_number_generator
label_desc: Use image node_id 4 for calling a global function with example usage: test_roi_images(rng) without return types